Black Oil - and too much of it????

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morgantheship

morgantheship

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Sep 26, 2008
44
Hunter 27 Port Washington
I installed a 2GM Yanmar engine in the spring. Before doing I removed any oil that was in the engine and put in fresh oil along with filters, etc. Throughout the season I would periodically check the oil level and the dip stick would always come out with pitch black oil.

Yesterday I was getting the boat ready for the winter haul out and changed the oil by pumping it out and I then added fresh oil (amber color 15-40 diesel oil) and then when I pulled the dip stick the oil was black and I had about a cup of black oil flow out of the dip stick hole.

My first question is...should the oil be black? And my second question is, am I somehow not getting all the oil out of the oil pan and then putting too much in causing it to flow out of the dip stick?

I am a bit concerned as I don't think that the oil should continue to be black. The engine seems to run fine, but I am not sure of how much oil I actually have in the engine as I can never get a read on the dip stick as the oil level aways seems to be high.

Is it possible that I am not pumping all the oil out? Any thoughts on what might be happening?
 
Don Crowther

Don Crowther

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Sep 4, 2007
776
Hunter 33.5 Elbow, Saskatchwen, Can.
Sounds like your not getting to the bottom of your oil pan. My hose goes in about 8.25". I found out that if i mark my suction hose with white tape I'm always sure of getting to the bottom of the oil pan.
My 2 gm only takes 2 qts. and my pump is clear so I can see how much oil comes out.
As for the colour that's a diesel for you. There will always be a small amount of oil you can't remove and after about 2-3 hrs of running the new oil will be black as well!!
Ok so I answered your questions in the wrong order but i hope that i answered them
Don
 
seadaddler

seadaddler

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Dec 19, 2006
5,832
Hunter 36 Punta Gorda
Pumping

Pumping all the oil out is not easy with the tube in the dip stick hole.
I spend a lot of time pumping every drop possible out but I don't think it all comes out,I have seen some times it does not all come out with the pumping
and so I keep pumping and try pushing the tube in and out trying to get it all out which takes longer than usual,I don't give up easy.
My 2007 Yanmar oil is always still black.
Nick
 
N

navigator97

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May 24, 2004
470
Hunter 33.5 Portsmouth, RI
Morgan---, One trick, that a friend taught me, is to put about a 10 inch or so length of rigid (but bendable) copper tubing on the end of the pumout tubing and place the copper tubing into the dipstick hole. this way you can feel bottom and move it around. With this method you can get most of the oil out - not all but most. I ONCE put it a measured amount of oil and it over filled and came out the dipstick hole. I don't do that any more. I put some in - measure on dipstick- put some in - measure - until it's at the full mark. Run engine a few minutes, then strop - wait - remeasure.

Dick
 
Buck420

Buck420

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Apr 22, 2001
497
Hunter 420 Norfolk, VA
seadaddler said:
Pumping all the oil out is not easy with the tube in the dip stick hole.
I spend a lot of time pumping every drop possible out but I don't think it all comes out,I have seen some times it does not all come out with the pumping
and so I keep pumping and try pushing the tube in and out trying to get it all out which takes longer than usual,I don't give up easy.
My 2007 Yanmar oil is always still black.
Nick
Click to expand
Nick,
If you're changing it w/ <100 engine hours between changes, and using CD oil, it really shouldn't be black.
To prevent the oil getting to that point, you might consider...
every 3-4 oil changes, do a double change.
IE, pump out the old oil, & change it w/ new Rotella-T (30w), and put on a new Wix (or other similar quality oil filter). Run the engine for about half hour under load. Let the engine cool; pump the (new, but now darkened) Rotella out. Put in new Yanmar oil and a new Yanmar oil filter.
By doing this, my oil, when changed after every 80-100hrs, (and doing a double change ~ every 300 hrs) is usually not much darker than when it was new; certainly not totally black.
 
Shell

Shell

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Sep 26, 2007
138
Catalina 30 standard JC/NYC
Every diesel I ever owned from a boat, truck or Mercedes, the oil is always black after a few days of running. If its not black then its not doing its job and may not be C rated
 
Buck420

Buck420

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Apr 22, 2001
497
Hunter 420 Norfolk, VA
Shell said:
Every diesel I ever owned from a boat, truck or Mercedes, the oil is always black after a few days of running. If its not black then its not doing its job and may not be C rated
Click to expand
So,... if a C(x) diesel engine oil doesn't quickly turn black under use, it's not not doing it's job.
Interesting !
 
B

Benny

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Sep 27, 2008
1,149
Hunter 320 Tampa, FL
Black oil is normal. Not getting all the oil out through the dipstick tube is part for the course. Review your refilling procedures. The amount required will vary depending on whether the filter is replaced or not. The way I do it is; I will fill 1/4 quarter at a time until I get a reading on the dipstick. After that I will add small amounts until I get around the 1/2 marking on the safe area and I'm done, I do not try to fill it to the top of the line because is to easy to overfill. If the filter was replaced I will crank the engine on, let it run for a minute an the turn it off. After the oil settles down I will tak another reading and once again fill slowly to around 1/2 inside the safe range. As long as the oil is in the safe range the engine is protected but if it is overfilled then engine seals may start to fail because of excessive oil pressure causing leaks and internal problems.
 
seadaddler

seadaddler

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Dec 19, 2006
5,832
Hunter 36 Punta Gorda
Black Oil

When I change oil it is not black at first but after running how long don't remember but it gets black.
I really believe with out a drain plug it is impossible to get it all drained and that is the reason why it turns black soon after changing it.
When I change my car oil it does not turn black and does stay nice and clean a long time,a combination of diesel and not draining it all out is why I think it turns black,my 2 cents.
I have been thinking of adding a drain plug but I just change the oil and filter sooner and more often,it's one of the cheaper things to do owning a boat.
Nick
 
S

Steve Dion

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Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
From my experience, the GM engines would turn the oil very dark after only a few hours of operation. The newer engines run much cleaner.

I would suggest that you take a look at a Moeller fluid extractor. They run about $70 but do a good job. You should be able to most of the oil out with a single attempt. Once you have all of oil out you can add another 1.5 - 1.8 quarts (just do not over fill). Start up your engine and let it warm up and drain all of this oil out again. Your engine should then be cleaned out.

Be SURE not to over fill it. DO NOT go by the engine specs when refilling. Use the dip stick to determine when it is full. You may also want to consider changing the transmission oil too. You do want to refill the transmission properly too. You just need to put the cap on the filler without screwing it in to determine when it is full. If you overfill the tranny, you can blow out the seals.
 
fwardell

fwardell

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Jun 30, 2009
9
2 28.5 Lake Norman NC
The oil in my 1985 Hunter 28.5 with Yanmar 2GM is always black when changed, and it certainly doesn't take long for new oil to blacken. I, too, like the Moeller oil changer because it really sucks and has a small wire down the suction tube to let you know when it reaches the bottom of the oil pan. Although it couldn't possibly drain all of the oil, I don't believe it misses much. I agree on refilling by checking the dip stick until full.
 
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